The casino operator said Thursday that it is calling a special meeting of shareholders to vote on the removal of Okada based on concerns about improper conduct. It is part of an ongoing battle between former friends and business partners Okada and company CEO Steve Wynn.

Okada used to be Wynn Resorts' single largest shareholder but the company tried to forcibly buy back his shares after it said it found that Okada made improper payments to overseas gambling regulators. The two have traded accusations of unethical or illegal conduct during the extended legal, and seemingly personal, dispute.

Wynn said its board has already deemed Okada unsuitable. It said a lengthy investigation by former FBI Director Louis Freeh uncovered evidence of improper conduct in connection with Okada dealings with Philippine officials.

Representatives for Okada's companies — Universal Entertainment Corp., based in Japan, and Aruze USA, based in Las Vegas — could not be reached for comment on behalf of Okada on Thursday.

Wynn Resorts also said Thursday that it is reducing the overall size of its board and increasing the percentage of independent directors as it tries to expand into new jurisdictions. The company had a 12-member board and has reduced it to nine members. If Okada is removed, that will shrink to eight.

The company said that Russell Goldsmith and Allan Zeman have stepped down from the board to devote more time to their other business commitments. Zeman will continue to serve as vice chairman of Wynn Macau Ltd. and as a director of that business as well. Directors Linda Chen and Marc Schorr have stepped down to reduce the number of inside directors but will continue to serve as executives of the company and on the board of its Macau business.